Missing-mass spectroscopy with the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Li</mml:mi><mml:mprescripts/><mml:none/><mml:mn>6</mml:mn></mml:mmultiscripts><mml:mo>(</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mo>,</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:mo>)</mml:mo><mml:mi>X</mml:mi></mml:mrow></mml:math> reaction to search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">H</mml:mi><mml:mprescripts/><mml:mi mathvariant="normal">Λ</mml:mi><mml:mn>6</mml:mn></mml:mmultiscripts></mml:math>

Hypernuclei, in which a proton or neutron in an atomic nucleus is replaced by a baryon that includes some number of valence strange quarks, are a unique probe of nuclear structure as well as of the strong interaction. This work provides significantly improved cross section data as well as missing-mass spectra in search of a possible ground state of the ${}_{\mathrm{\ensuremath{\Lambda}}}^{6}$H hypernucleus, whose existence had been suggested in an earlier experiment using a different reaction. While the new experiment had considerable sensitivity, the authors observed zero events in the mass range of the previous experiment, suggesting that the binding energy of this hypernucleus is not as large as previously suggested.